Electronic components mounted on circuit boards generate heat which must be dissipated for their proper functioning. In low total power or low power density applications, air is typically used to cool these electronic components. The use of fans, ducting and/or heatsinks to accomplish this is well understood and widely used in industry.
In high total power or high power density applications, air provides insufficient cooling because of its relatively low thermal capacity. In these applications, liquids can be used to provide significantly improved cooling, but provisions must be made to contain the liquid so that the electronic components are not directly contacted by the liquid.
One conventional technique for cooling electronic components uses a liquid-cooled plate. Conventional liquid-cooled cold plates are typically made of copper or aluminum, although other materials can be used. The cold plate includes channels within it for distributing the cooling liquid, and inlets and outlets for enabling the liquid to enter and exit the cold plate. The cold plate is then mated to the electronic circuit board. The electrical components on the circuit board that touch the cold plate are thereby cooled because of their close proximity to the cooling liquid, but at no time do the electrical components actually touch the cooling liquid directly.
There are a wide variety of cold plate technologies presently available. Lower performance cold plates typically use metal tubes to distribute the liquid and higher performance cold plates typically use vacuum braze construction. Vacuum brazing allows the use of high performance fins to be placed within the liquid channel at locations where better heat transfer is required by the cold plate surface.
In many applications there are just a few electronic components on a circuit board that actually require liquid cooling. The present invention provides for cost effective cooling for individual components as well as for entire circuit boards.